Shares of CSX (CSX) are plunging, down about 8%, after the railroad company’s CEO is taking an unexpected leave of absence due to health issues. CSX is still up about 48% for the year.

Costco (COST) shares are rallying after it beat earnings expectations. The warehouse club proved it’s holding its own in the food price wars, with same store sales growing nearly 8%.

Hess (HES) is once again under pressure from activist hedge fund Elliott Management, which reportedly called for the removal of the CEO or a sale of part or all of the company. Elliott Management also wants the energy giant to cut its dividend to fund stock buybacks.

Upgrades and downgrades

Under Armour (UAA) is surging on an upgrade to Buy from Hold at Stifel Nicolaus, with a $17 price target. Analysts cited evidence of improving sales quality and cost-structure management.

Crocs (CROX) received an upgrade to Buy at Stifel Nicolaus, with analysts noting growth opportunities in China, Korea and Europe.

Teva Pharmaceuticals (TEVA) shares are up 7% after Goldman Sachs upgraded the generic drug maker to buy. Analysts are positive on the firm’s turnaround strategy.

Shares of Foot Locker (FL) are trading higher on an upgrade to Buy from Hold at Canaccord. The firm has a $64 price target on the athletic wear maker, noting that current headwinds for the industry are most likely cyclical rather than structural.

Fitbit (FIT) shares are sinking on a downgrade to Sell at Stifel Nicolaus, with analysts citing concerns over profitability and revenue.